Compare the functions of the CNS & PNS
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Identify the principle parts of the nervous
system
Describe the cells that make up the nervous
system
Describe what starts and stops a nerve
impulse (action potential)
The role of neurotransmitters
Compare the functions of the CNS & PNS
Identify the principle parts of the brain
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CNS = spinal cord & brain
PNS = nerves carry (tissue) impulses to and
from brain
Motor Output side of chart has 2 divisions:
somatic and autonomic
Focus Somatic 1st then Autonomic
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Requires only one neuron system: CNS to cell
12 pairs cranial nerves
◦ From brain’s underside/brain stem
◦ Brain to muscles, glands, head, neck, thorax,
abdomen
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31 pairs spinal nerves
◦ Originate from spinal cord
◦ Dorsal root ganglia– sensory incoming AP from
tissues to cord
◦ Ventral root ganglia– motor outgoing AP away from
cord to body
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Connects CNS to body parts
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Spinal Reflexes – require no conscious thought –
processes @ spinal cord only
E.g. flexor reflex – withdrawal of foot from
something sharp
Knee-jerk reflex (check up) – tap below patella
causes contraction of thigh and upward
movement of foot and leg
Stretch (quadriceps) reflex – posture maintenance
– stand and move w/out having to think about it
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Sympathetic – stress / high activity
Parasympathetic – resting, homeostasis
2 neuron system to transmit impulses to
target cells
1st neuron - preganglionic in CNS
2nd neuron – postganglionic outside CNS &
extending to the far reaches of the body
(glands/organs)
Sympathetic & Parasympathetic oppose each
other – work antagonistically for homeostasis
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Neurotransmitters
◦ Sympathetic – norepinephrine (adrenalin) - stress
◦ Parasympathetic – acetylcholine - relax
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Central location & action
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Integrating & processing of information
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Info in  CNS  Complex Output
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Normal thoughts
Dark thoughts
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Reflexes and the reflex arc – terms 142-143
Learning Target #5 (Nervous System) p 135:
Describe the structure of a reflex arc and the
function of a reflex
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Bone, meninges & blood-brain barrier
Bone: skull & hollow vertebrae
Meninges: CNS enclosed by 3 membranous
layers
◦ Out  In
◦ Dura matter – arachnoid matter – pia matter
CNS is bathed in cerebrospinal fluid
 Fills the space between the arachnoid matter
& pia matter
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Functions as a liquid shock absorber
Isolates the CNS from infection (meningitis:
bacterial or viral infection of meninges can
spread to CNS)
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CSF is like the interstitial fluid that bathes all
cells but it does not exchange substances as
freely with blood
Capillaries in this area are “tight” = not leaky
& substances must pass through the actual
capillary cells (vs. slipping between narrow
slits of adjacent capillary cells) to get from
blood to the brain
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Lipid soluble substances pass easily (O & CO2)
Glucose requires active transport
Larger molecules: proteins, viruses, bacteria
kept out
What can pass through BBB?
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Alcohol
Caffeine
Nicotine
Cocaine
Anesthetics
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Information super highway for APs between
the brain and the body
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Recall – spinal reflexes don’t involve brain
and therefore are considered “unconscious”
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Size – about the diameter of your thumb
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Location – runs from the base of your skull to
the area of the 2nd lumbar vertebra ~ 17
inches
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Outer portions of the cord consist of bundles of
axons = nerve tracts that are mylenated
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white matter – ascending sensory nerves
& descending motor nerves
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Inner portions consist of cell bodies, dendrites,
neuroglial cells that are unmylenated
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gray matter – here sensory & motor
neurons synapse & transmit to the brain…